Many processes have been disclosed for the preparation of 2-chloro-1,1,1,2-tetrafluoroethane (i.e., HCFC-124 or CHClFCF.sub.3) and pentafluoroethane (i.e., HFC-125 or CHF.sub.2 CF.sub.3). Typical processes are described in GB 1,578,933 and U.S. Pat. No. 3,755,477. GB 1,578,933 suggests hydrodehalogenation of various halogenated ethanes including 2,2 -dichloro-1,1,1,2-tetrafluoroethane (i.e., CFC-114a or CCl.sub.2 FCF.sub.3) and pentafluoroethane, to form 1,1,1,2-tetrafluoroethane (i.e., HFC-134a or CH.sub.2 FCF.sub.3) and HCFC-124. U.S. Pat. No. 3,755,477 discloses a process for producing fluorinated aliphatic hydrocarbons which comprises fluorinating a halogenated aliphatic hydrocarbon (e.g., 1,1,1-trichloroethane or trichloroethylene) using a gas phase reaction with hydrogen fluoride in the presence of a chromium oxide catalyst. Example 23 therein illustrates using tetrachloroethylene as a raw material, with formation of 20% 2,2-dichloro-1,1,1-trifluoroethane (i.e., CHCl.sub.2 CF.sub.3 or HCFC-123), 20% HCFC-124, 30% HFC-125 and 20% chloropentafluoroethane (i.e., CClF.sub.2 CF.sub.3 or CFC-115).
It is difficult to predict the supply/demand situation for any given hydrofluorocarbon, hydrochlorofluorocarbon or their precursors. There is thus an incentive for developing numerous routes to commercially valuable hydrofluorocarbons and hydrochlorofluorocarbons. HFC-125 and HCFC-124 are useful as refrigerants, blowing agents, fire extinguishants and propellants. Therefore, there is continuing interest in developing efficient methods of producing these materials.